Behavioural and Cognitive Psychotherapy, 2011, 39, 129–138 First published online 10 November 2010 doi:10.1017/S1352465810000548
Cognitive Behavioural Therapy for Auditory Hallucinations: Effectiveness and Predictors of Outcome in a Specialist Clinic Neil Thomas Monash Alfred Psychiatry Research Centre and La Trobe University, Australia
Susan Rossell Monash Alfred Psychiatry Research Centre and Swinburne University, Australia
John Farhall and Frances Shawyer La Trobe University, Australia
David Castle University of Melbourne, Australia
Background: Cognitive behavioural therapy has been established as an effective treatment for residual psychotic symptoms but a substantial proportion of people do not benefit from this treatment. There has been little direct study of predictors of outcome, particularly in treatment targeting auditory hallucinations. Method: The Psychotic Symptom Rating Scales (PSYRATS) and Positive and Negative Syndrome Scale (PANSS) were administered pre- and post-therapy to 33 people with schizophrenia-related disorders receiving CBT for auditory hallucinations in a specialist clinic. Outcome was compared with pre-therapy measures of insight, beliefs about the origin of hallucinations, negative symptoms and cognitive disorganization. Results: There were significant improvements post-treatment on the PSYRATS and PANSS Positive and General Scales. Improvement on the PSYRATS was associated with lower levels of negative symptoms, but was unrelated to overall insight, delusional conviction regarding the origins of hallucinations, or levels of cognitive disorganization. Conclusions: Lack of insight and presence of formal thought disorder do not preclude effective cognitive-behavioural treatment of auditory hallucinations. There is a need to further understand why negative symptoms may present a barrier to therapy. Keywords: Schizophrenia, psychosis, auditory hallucinations, cognitive behavioural therapy, predictors, insight, negative symptoms.
Reprint requests to Neil Thomas, Monash Alfred Psychiatry Research Centre, Level 1, Old Baker Building, The Alfred, Commercial Road, Melbourne, Victoria 3004, Australia. E-mail:
[email protected] © British Association for Behavioural and Cognitive Psychotherapies 2010
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Cognitive behavioural therapy (CBT) has become established as an evidence-based treatment for reducing the emotional and behavioural impact of medication-resistant psychotic phenomena such as hallucinations and delusions in schizophrenia (National Institute for Clinical Excellence, 2009; Wykes, Steel, Everitt and Tarrier, 2008). However, up to 50% of people fail to respond to this therapy (Garety, Fowler and Kuipers, 2000). In order to facilitate the recovery of people who have ongoing distressing psychotic experiences there is a need to understand what the barriers are to benefiting from psychological treatment. In spite of there being over 30 randomized controlled trials of CBT for psychosis (Wykes et al., 2008), there have been relatively few reports of predictors of outcome. Some trials have reported that people with more severe and longstanding experiences of psychosis are less likely to show improvement following CBT (Durham et al., 2005; Tarrier et al., 1998), but these factors were identified as applying to both CBT and control treatments, rather than specifically applying to CBT. Identification of these broad variables also has limited implications for how to improve therapy outcomes. Of more clinical importance are specific clinical characteristics that may predict therapy response. A study of a wide range of predictors was conducted as part of one of the earlier clinical trials of CBT for psychosis (Garety et al., 1997). This study’s key finding was that post-treatment outcome was related to a pre-therapy measure of whether service users could acknowledge the possibility that they were mistaken in their delusional beliefs, and also to a dimension of insight relating to awareness of the social disability associated with psychosis. Other variables, including IQ, verbal fluency, and probabilistic reasoning, were found to be unrelated to outcome. Another more comprehensive examination of predictors of outcome was conducted on data from the Insight into Schizophrenia Trial (Turkington, Kingdon and Turner, 2002), which examined a brief course of six sessions of CBT for psychosis delivered by community psychiatric nurses; higher levels of delusional conviction and lower overall levels of insight predicted poorer outcome (Brabban, Tai and Turkington, 2009; Naeem, Kingdon and Turkington, 2008). These findings, relating to the overlapping constructs of strong delusional conviction, and lack of insight into psychotic experiences as mentally generated, suggest that CBT for psychosis may be less successful when people hold rigid delusional explanations of their experiences. This has been interpreted as there being a need for a “chink of insight” to conduct belief modification with people experiencing the reality distortion inherent in psychosis (Garety et al., 2000). This has received support from a qualitative study of experiences of therapists delivering CBT for psychosis (McGowan, Lavender and Garety, 2005). However, a difficulty in interpreting these findings is that they have been from trials of CBT for persisting positive symptoms in general, which may have involved addressing either delusions, hallucinations, or both in combination. Consequently, it is unclear whether insight and belief conviction are important solely in the treatment of delusions or also when hallucinations are the focus of therapy. Indeed, if poor insight and high delusional conviction impede the process of belief modification, this might not be a barrier to successful therapy if applying more behavioural methods such as coping strategy enhancement (Tarrier et al., 1993). A further limitation of studies combining CBT for delusions and hallucinations is that measurement of outcome has been reliant upon the use of broad mental state measures such as the Positive and Negative Syndrome Scale (Kay, Opler and Lindenmayer, 1987), which may be relatively insensitive to treatment effects on the specific symptoms targeted by therapy.
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Together with heterogeneity arising from differences in service user presentation and more than one potential focus of therapy, this may lead to further specific predictor effects being obscured. Another strategy in examining predictors of outcome is to study CBT delivered for a specific target symptom. Auditory hallucinations, typically experienced as hearing voices, are one of the most common such targets, and they represent a discrete phenomenon for which more focused measures are available. Examining CBT for voices allows the role of belief conviction and insight to be clarified with this particular symptom. Also, by examining therapy targeted at a specific phenomenon with a dedicated outcome measure, other sources of variability in outcome are reduced, which may highlight other predictor variables. A starting point in examining predictors of outcome in CBT for voices is to examine the influence of other psychotic phenomena on outcome. The symptoms of schizophrenia have been conceptualized in terms of three statistically-derived symptom clusters, which relate to distortion of reality, disorganization and negative symptoms (Liddle, 1987). Reality distortion symptoms include hallucinations, together with delusions and lack of insight. It is typical for auditory hallucinations to be associated with delusional beliefs about the origins and identity of voices (Chadwick and Birchwood, 1994). It is possible that strong conviction in these beliefs may present a barrier, not only to modifying these beliefs themselves, but also to restructuring related beliefs about voice power and control over the experience (Chadwick and Birchwood, 1994; Trower et al., 2004). Similarly, lack of insight into the origins of voices as internally generated may make it more difficult to establish a rationale for a psychological treatment, which may hinder formation of a working alliance. Disorganization most frequently manifests as formal thought disorder, which often involves the person’s speech frequently slipping into loosely related or unrelated topics. This may present a problem in the process of therapy as the person may be hard to direct through Socratic dialogue, and may have difficulties following the thread of therapy. Negative symptoms such as affective blunting, amotivation and poverty of thought may make it difficult for the therapist to establish a working alliance with the service user and for the service user to engage in the sessions and complete between-session exercises. Indeed, a non-significant trend has been observed for affective blunting to be associated with a poorer outcome in CBT for psychosis (Brabban et al., 2009), suggesting that further study of negative symptoms is warranted. The present study provides an examination of these potential predictors of outcome in an open trial of CBT for auditory hallucinations within a specialist clinic.
Method Participants Participants were people seen in a specialist outpatient clinic providing CBT for auditory hallucinations to people referred by public mental health services, private psychiatrists and general practitioners alongside their routine care. Inclusion criteria were: (a) a diagnosis of a schizophrenia or schizoaffective disorder; (b) current auditory hallucinations in the form of voices, occurring at least once per week; (c) voices associated with significant subjective distress; (d) history of voices for at least one year; and (e) currently prescribed antipsychotic medication. Of the 33 participants, 21 (64%) were male and the overall mean age was
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36.4 years (SD 8.99). Ten (30%) were in paid or voluntary employment. Participants reported hearing voices for an average of 13.5 years (SD 8.23). All participants had already been trialled on at least two separate antipsychotics prior to the outset of therapy.
Therapy Participants received weekly to fortnightly treatment sessions up to a maximum of 24 sessions, with a mean therapy length of 12.1 (SD 5.98) sessions. In all, 26 participants received therapy from a clinical psychologist with 7 years’ experience of CBT for psychosis, and the remaining 7 participants received therapy from other psychologists under fortnightly supervision of the main therapist. Therapy was based upon the manual of Fowler, Garety and Kuipers (1995) and broader literature on the psychological treatment of auditory hallucinations (e.g. Chadwick and Birchwood, 1994; Morrison and Renton, 2001; Tarrier, 1992). This included the development of a formulation based upon assessment of voice phenomenology, other psychotic symptoms, antecedents of and responses to hearing voices, and appraisals of voices that may mediate distress. This formulation was used to guide treatment, incorporating elements of building an adaptive shared understanding of hallucinatory experience, coping enhancement, developing adaptive responses to voices, and modifying appraisals relating to distress through Socratic questioning and behavioural experiments.
Measures The following therapist-administered measures were completed at the beginning and end of therapy: The Psychotic Symptom Rating Scales (PSYRATS; Haddock, McCarron, Tarrier and Faragher, 1999) is an interview-based set of clinician rating scales, comprising 11 5-point items assessing different dimensions of voice experience, such as frequency, distress, impact upon functioning. The total score was used as the main outcome measure, and the beliefs about origins of hallucinations scale (item 5) was used to assess strength of belief that voices heard are of external origin. High scores on this item correspond to strong delusional conviction that voices are externally generated, and low scores correspond to complete belief that voices are internally generated. The inter-rater reliability of the PSYRATS is excellent, including for specific items, and it shows good test-retest reliability and validity (Haddock et al., 1999; Drake, Haddock, Tarrier, Bentall and Lewis, 2007). Positive and Negative Syndrome Scale (PANSS; Kay et al., 1987) is an interview-based measure of positive and negative psychotic symptoms, and other symptoms associated with psychosis, on three scales (positive, negative and general), comprising 30 7-point items. The negative syndrome scale was used to index negative symptoms, and the cognitive disorganization item (P2) was used to assess formal thought disorder. The PANSS shows excellent inter-rater reliability and validity (Bell, Milstein, Beam-Goulet, Lysaker and Cicchetti, 1992; Kay, Opler and Lindenmayer, 1988). The Schedule for the Assessment of Insight (SAI; David, Buchanan, Reed and Almeida, 1992) is a clinician rating scale assessing three dimensions of insight into illness (awareness of illness, treatment compliance, and relabelling psychotic experiences) with a total score of 0–14; it has good inter-rater reliability and validity (David et al., 1992).
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Table 1. Pre-treatment scores on measures and correlations with outcome
PSYRATS total PANSS positive symptoms PANSS negative symptoms PANSS general symptoms Belief about origin of voices Schedule for Assessment of Insight Cognitive disorganization
M
SD
rpb
p
29.82 16.58 12.67 27.67 2.61 10.82 2.00
4.12 5.82 7.69 6.49 0.97 3.09 1.70
+.13 +.06 −.64 −.18 −.11 +.12 +.07a
.46 .74
